High FG in Belgian dry stout

[Mackie]

Hi guys, a couple weeks ago I brewed a 2.5 gal Belgian-style dark beer with orange peels with some leftover grains I had on hand:

64.7% Vienna malt
20.6% Belgian Candi sugar
9.4% Chocolate malt (ground and added to the end of the mash for 3-5 mins)
3.3% Acid malt
2.0% Aromatic malt

I made a rough imprecise half litre starter of 3522, mashed at 152f hopped with 25 ibus Magnum at 60min and added a little dried orange peel to the end of the boil. OG was 1.051 and I was really hoping to get a super dry, dark-saison-esque crisp dark beer, like at least under 1.005 FG. Beersmith expected 1.004.

I got a huge sulfur smell coming off the beer (never gotten that before in any beer let alone with 3522 but I have seen others on here say they get it and it's normal) and more notably an oddly thin krausen with big bubbles that lasted about 2 days (don't have any pictures - my guess was it was from the high amount of candi sugar) and about a week after took a gravity reading and it was at 1.014. I ramped the temp up to 24C and its been steady at 1.011 for a few days. I've even tried adding a bit of 3711 and nothing happened. It's got some weird phenolic off flavours anyways so I imagine this batch isn't going to be anything to write home about regardless.

I will probably just bottle it as is and it'll be drinkable but for the sake of learning if anyone has any ideas why fg is that high (I do realize its a pretty reasonable fg for a ~5% beer) and why 3711 did nothing would love to hear em. Could underpitching cause a higher fg? Stale malt? oh actually I think I may have added the candi sugar at the beginning of the boil could that cause it to like undergo a maillard reaction and become more complex sugars..?

 

[VikeMan]

I entered this into BrewCipher. Assuming a 60 minute mash, I would expect this to get down to about 1.008 (with the original yeast strain). So at least that's closer to where you're at than 1.005. (BeerSmith doesn't care about the types of grains in the mash when predicting attenuation.)

Regarding the 3711...I suspect that it will eventually bring your SG down, given time. The use of (normally) unfermentable dextrins by diastaticus strains (like 3711) can be slow.

 

[Mackie]

Interesting, thanks! I didn't know that about beersmith not caring about the malt but I see now the estimated FG does not change when I add or remove the Chocolate malt from the recipe so thats 3 or 4 points right there! It's my first time using vienna malt but I imagine that is another point or two at least! Didn't occur to me that this was a software issue lol

But still, no harm giving it a couple more weeks in the fermenter to see if I can't get a few more points!!

 

[Gusso]

Maybe try Gulo next time. I just kegged a BdG that had an OG of 1.069 and finished at 1.003. I haven't sampled it yet but I have high hopes!